4 V to 40 V input, fixed 12 V output at 3 A
Input range spans 4 V to 40 V, making it usable off unregulated rectified supplies, 12 V or 24 V rails, and battery stacks that sag under load. The fixed 12 V output at 3 A continuous is the headline load rating — size the inductor and output capacitor for that current, not the 52 kHz switching frequency.
The TO-220-5 package with through-hole mounting is a reflow-oven exception: it goes through wave solder or hand-solder, not the paste reflow profile. MSL is not a concern for a leaded power package, but the tab (pin 4, substrate) needs a thermal pad or heatsink — the junction-to-case thermal path is the limiting factor for sustained 3 A at high ambient.
This is the lead-free / NOPB suffix version of the original LM2576T-12. Pin-compatible, same switching frequency, same inductor selection. If your BOM already calls out the older LM2576T-12, this is a drop-in replacement that keeps you RoHS-compliant without a board respin.